code: def test_registry_has_builtin_token_indexers(self):
      assert (
          TokenIndexer.by_name("single_id").__name__
          == "SingleIdTokenIndexer"
      )
      assert (
          TokenIndexer.by_name("characters").__name__
          == "TokenCharactersIndexer"
      )
  
imports: import inspect
  import os
  from typing import List
  import pytest
  from allennlp.common.checks import ConfigurationError
  from allennlp.common.registrable import Registrable
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.util import push_python_path
  from allennlp.data.dataset_readers.dataset_reader import DatasetReader
  from allennlp.data.token_indexers.token_indexer import TokenIndexer
  from allennlp.data.tokenizers.tokenizer import Tokenizer
  from allennlp.modules.text_field_embedders.text_field_embedder import TextFieldEmbedder
  from allennlp.modules.token_embedders.token_embedder import TokenEmbedder
  from allennlp.nn.regularizers.regularizer import Regularizer
label_desc: Use image node_id 3 for calling the TestRegistrable obj's underlying member method code with example usage: obj.test_registry_has_builtin_token_indexers() without return types